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// Functor implementations -*- C++ -*-
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2011
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996-1998
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/** @file backward/binders.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{functional}
*/
#ifndef _BACKWARD_BINDERS_H
#define _BACKWARD_BINDERS_H 1
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// 20.3.6 binders
/** @defgroup binders Binder Classes
* @ingroup functors
*
* Binders turn functions/functors with two arguments into functors
* with a single argument, storing an argument to be applied later.
* For example, a variable @c B of type @c binder1st is constructed
* from a functor @c f and an argument @c x. Later, B's @c
* operator() is called with a single argument @c y. The return
* value is the value of @c f(x,y). @c B can be @a called with
* various arguments (y1, y2, ...) and will in turn call @c
* f(x,y1), @c f(x,y2), ...
*
* The function @c bind1st is provided to save some typing. It takes the
* function and an argument as parameters, and returns an instance of
* @c binder1st.
*
* The type @c binder2nd and its creator function @c bind2nd do the same
* thing, but the stored argument is passed as the second parameter instead
* of the first, e.g., @c bind2nd(std::minus<float>,1.3) will create a
* functor whose @c operator() accepts a floating-point number, subtracts
* 1.3 from it, and returns the result. (If @c bind1st had been used,
* the functor would perform <em>1.3 - x</em> instead.
*
* Creator-wrapper functions like @c bind1st are intended to be used in
* calling algorithms. Their return values will be temporary objects.
* (The goal is to not require you to type names like
* @c std::binder1st<std::plus<int>> for declaring a variable to hold the
* return value from @c bind1st(std::plus<int>,5).
*
* These become more useful when combined with the composition functions.
*
* @{
*/
/// One of the @link binders binder functors@endlink.
template<typename _Operation>
class binder1st
: public unary_function<typename _Operation::second_argument_type,
typename _Operation::result_type>
{
protected:
_Operation op;
typename _Operation::first_argument_type value;
public:
binder1st(const _Operation& __x,
const typename _Operation::first_argument_type& __y)
: op(__x), value(__y) { }
typename _Operation::result_type
operator()(const typename _Operation::second_argument_type& __x) const
{ return op(value, __x); }
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 109. Missing binders for non-const sequence elements
typename _Operation::result_type
operator()(typename _Operation::second_argument_type& __x) const
{ return op(value, __x); }
} _GLIBCXX_DEPRECATED;
/// One of the @link binders binder functors@endlink.
template<typename _Operation, typename _Tp>
inline binder1st<_Operation>
bind1st(const _Operation& __fn, const _Tp& __x)
{
typedef typename _Operation::first_argument_type _Arg1_type;
return binder1st<_Operation>(__fn, _Arg1_type(__x));
}
/// One of the @link binders binder functors@endlink.
template<typename _Operation>
class binder2nd
: public unary_function<typename _Operation::first_argument_type,
typename _Operation::result_type>
{
protected:
_Operation op;
typename _Operation::second_argument_type value;
public:
binder2nd(const _Operation& __x,
const typename _Operation::second_argument_type& __y)
: op(__x), value(__y) { }
typename _Operation::result_type
operator()(const typename _Operation::first_argument_type& __x) const
{ return op(__x, value); }
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 109. Missing binders for non-const sequence elements
typename _Operation::result_type
operator()(typename _Operation::first_argument_type& __x) const
{ return op(__x, value); }
} _GLIBCXX_DEPRECATED;
/// One of the @link binders binder functors@endlink.
template<typename _Operation, typename _Tp>
inline binder2nd<_Operation>
bind2nd(const _Operation& __fn, const _Tp& __x)
{
typedef typename _Operation::second_argument_type _Arg2_type;
return binder2nd<_Operation>(__fn, _Arg2_type(__x));
}
/** @} */
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif /* _BACKWARD_BINDERS_H */
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